The whole purpose of manufacturing is to sell a product that competes with other brands in quality, styling, etc., a product that has reasonable reliability, meets government standards and regulations, yet still turn some sort of profit. There is a lot more to it, but that's the very basic idea.
And therein lies many issues for engineering.
Remember they still have to turn a profit. Meaning if a JD of the same size is $5 less expensive, they're gonna cut $7-$10 out somewhere, maybe getting a bolt cheaper from a different supplier or whatever.
So on a loader pin you have a lot of options. The way the 525's are designed is the same as they've been for decades. Bolt through the end of the pin, and it hasn't really been an issue to my knowledge. If it was, it was minor enough for owners to just toss another bolt in. Excavators have roll pins in the bucket pivot and those roll pins are a pain in the backside!! Ideally you need a roll pin punch to remove them, and when removing they are usually junk--IF you can get them out at all. I burned many of them out, and replaced the pins-on brand new equipment (bucket swap, QA install or Thumb install). The flanged bolts are also a thorn in my side because folks bust the head of the bolt off on rocks/dirt/whatever and then I got the joys of drilling a bent bolt out of a hole. Some of them were through-bolted with a nut on back and those were easy as long as the pin's flange wasn't bent up, even then just replace it. But therein lies the issue. Customer gripe about the cost of a pin + labor + bolting it back on. B7100 loaders and some of the smaller B series years ago had nothing but COTTER PINS holding loader pins in. Some mad customers over there, but ya know what? It cost the dealer MORE money to assemble those than it does a LA525. We had to put the pin through, line the hole up, then stuff a cotter pin into the hole, and fight with it to bend the legs of the cotter pin sufficiently. It cost Kubota more in warranty claims because the dealer setup techs would oftentimes get in a hurry (Imagine that) and wouldn't bend the legs far enough, pin came out, bent the cheap loader frame or whatever. So they changed to through-bolts like the 525's are designed with now. They are inexpensive, and fewer problems with them. On the cotter pins some of them you could NOT get to them, the hood was in the way, all kinds of stuff-you couldn't get any dikes in there to bend the legs. And you ain't bending the legs over on a 1/4" cotter pin by hand.
No matter how it's designed people are going to gripe about it, and Kubota's engineers know this. Thus, the least expensive way to retain the pins on the standard L series that is an acceptable method as far as reasonable reliability is to through-bolt them. And no the bolts do not get fully tightened. You run the nut down until there is approx 1/4" of play and you're done. This is to allow the bolt to float in the pin so it'll come out later. Also, it allows the pin to float just a little bit which keeps the pin from seizing into the loader frame and/or bucket (or cylinder). Some of the M series have a boom pin that is flanged and bolted, and almost all of the ones I've done were seized completely because there is no play, no way for the pin to keep itself from rusting/seizing into the bore. Common for those to just shear the flange off, and on the ones that had a welded pin and a snap, those were even more common to seize and shear. So the sensible solution? Grease them!! Well guess what, it's inconvenient for people to take 5 minutes out of their "maintenance" schedule to put a grease gun on things, that is if they even know it has a fitting. So many times, I've replaced entire engines, transmissions, pins, blades, you name it--because the owners don't even know "they're supposed to check that". I had mentioned this to an older gentleman who grew up working on 8N Ford's and 850's, etc and he said it's nothing new, but there's more of it now because there are more people now. Fair enough. I guess.
and yes I know of at least one of the engineers at Kubota USA (Georgia) and that person does in fact own and use a Kubota. This person and I spoke a while back, I will call him Kevin. I told Kevin that I think some things on the equipment could have been better designed, and he agreed--however if we designed them to meet everyone's needs, it would weigh 100,000 lbs, it would be larger than an 18 wheeler, ugly as sin, and would cost $250,000. But it would be easier to work on. As he said, you can't please everyone but they don't stop trying.